Volcanic ash

VOLCANIC ASH (EN: volcanic ash, cinder; DE: Vulkanasche; FR: cendre volcanique; ES: ceniza volcanica; RU: вулканический пепел) is the pyroclastic material (tephra) with the size of the particles of less than 2 millimetres, which is formed as the result of the crushing, by the volcanic explosions, of the liquid lava, which is erupting, and of the rocks, which are forming the volcano, namely, of the products of the earlier eruptions. Depending on the size of the particles, on the strength of the eruption, and on the wind, the volcanic ash can settle at the significant distance from the place of the eruption, thus forming the orderly marker horizons. So, for example, during the eruption of the Bezymianny volcano (Kamchatka) during the 1956, the volcanic ash has flown up to the United Kingdom, and during the eruption of the Krakatau volcano (Indonesia) during the 1883, this ash has flown around the Earth almost two times. This peculiarity of the volcanic ash is used within the stratigraphy (the tephrachronological method for the correlation of the strata of the rock). The volcanoes of the Earth eject annually approximately 3•10^9 tonnes of the volcanic ash on average.

The volcanic ash is used for the production of the lightweight concretes, tare glass, cements, thermal insulating materials, filtering masses, and so on. Besides these purposes, the volcanic ash is used as the medium for the growing of the plants. See also the "Pyroclastic rocks" article.